Complex State Flows

Problem Statement

Multi-step operations with dependencies between steps are prone to ordering bugs, missing preconditions, and untested edge cases. Even without a formal state machine library, thinking in states and transitions prevents bugs.

Pattern: State Machine Thinking

Problem: Complex flows have implicit states that aren't modeled, leading to invalid transitions.

Example - Retake flow states:

IDLE → LOADING_COMPLETED → ENABLING_RETAKE → CLEARING_ANSWERS → READY → ANSWERING → MERGING → SUBMITTING → COMPLETE
                                                                                                              ↓
                                                                                                           ERROR